Coast FIRE Calculator
Coast FIRE is the moment your investments no longer need you: enough saved that compounding alone finishes the job by retirement age. Find your coast number — and when you'll cross it.
Estimates are for illustration and education only — not financial advice. Use a real (after-inflation) return so all figures stay in today's dollars.
Coast FIRE, explained
The FIRE movement (Financial Independence, Retire Early) centers on your FIRE number — annual spending ÷ withdrawal rate, typically 25× yearly expenses. Coast FIRE is the gentler milestone: the amount which, invested today and never added to again, compounds into that full FIRE number by your retirement age. Formula: coast number = FIRE number ÷ (1 + r)years left.
Why it changes careers, not just spreadsheets
Crossing your coast number means retirement is fully funded — every dollar you earn after that only needs to cover today's life. People use it to switch to lower-paying meaningful work, go part-time, or start a business, all without touching the retirement outcome. It's the cheapest form of freedom compounding can buy.
Why age dominates the math
The coast number grows steeply as time shrinks: with a $1.2M target and 5% real returns, you need about $220k at 30, but $440k at 44 and $730k at 55. Every decade earlier roughly halves the requirement — the discounting works exactly like our present value calculator, run against your retirement date.
Use real returns
Because your retirement spending is entered in today's dollars, use a real (after-inflation) return — commonly 4–6% for a stock-heavy portfolio, versus ~7–10% nominal. That keeps the FIRE number, coast number and projections all in money you can actually reason about. For the full accumulation-and-drawdown picture, see the retirement calculator.
Coast FIRE numbers by age
What you need invested today to coast to a $1M nest egg at 65, at different real returns.
| Age today | 4% real | 5% real | 6% real |
|---|---|---|---|
| 25 | $208,289 | $142,046 | $97,222 |
| 30 | $253,415 | $181,290 | $130,105 |
| 35 | $308,319 | $231,377 | $174,110 |
| 40 | $375,117 | $295,303 | $232,999 |
| 50 | $555,265 | $481,017 | $417,265 |
Figures are rounded, assume annual compounding of real returns — illustrative only.
What "Coast FIRE" actually means
Coast FIRE is the point where your invested savings, left completely alone, will compound into a full retirement by your target age. After that milestone you only need to cover today's expenses — no more retirement saving required.